Light-sensitive aqueous developable copying material and product by coating process thereof utilizing polysiloxane and alkylene oxide copolymer as coating aid

ABSTRACT

The present application describes a light-sensitive copying material comprising a support and a light-sensitive layer which contains a surface-active polysiloxane comprised of dialkyl siloxane units and oxyalkylene units. By the addition of the polysiloxane a more uniform coating is achieved, even if only a single solvent is used for the coating solution.

This is a continuation of application Ser. No. 273,004, filed June 12,1981, now abandoned.

BACKGROUND OF THE INVENTION

The present invention relates to a light-sensitive copying material andto a process for the manufacture of such material, which includes thegeneral steps of coating a support with a solution of the components ofthe light-sensitive layer which are dissolved in a solvent, preferablyin an organic solvent, and drying the layer.

Usually, light-sensitive copying materials of various descriptions aremanufactured in such a way that supports consisting of metals, plasticfilms, paper, fabrics and the like are coated as evenly as possible withsolutions of the layer components, and these solutions are then driedunder conditions which ensure the formation of layers which are asuniform as possible.

The layer components used generally comprise light-sensitive orphotoconductive compounds or combinations of such compounds, binders,dyes, pigments, plasticizers, fillers, polymerizable compounds,stabilizers and the like. The components are preferably dissolved inorganic solvents and, occasionally, also in water or mixtures of waterand organic solvents.

In industrial scale coating and in continuous manufacturing processes,mixtures of several solvents which have different evaporation numbersare practically always used, in order to obtain a substantiallycontinuous transition from the liquid film phase to the dry layer and toprevent, if possible, any disintegration during drying. In most cases,whis is achieved by a combination of solvents having a good dissolvingpower with non-solvents; the vapor pressures and evaporation numbers ofthe components are chosen in such a way that the non-solvents are thefirst to evaporate in the drying process. Thus, layers of an adequatecoating quality are produced, but unless they are colorless, theselayers still exhibit a certain irregularity which is referred to as"cloudiness".

The term "cloudiness" denotes the presence of contiguous layer areas oflighter and darker shades which have diameters ranging from about 1 to10 mm. Scanning electron micrographs (SEM) of sections through copyinglayers have revealed that variations in color density can be attributedto differences in the layer thickness.

It is presumed that, until the gel phase is reached in the dryingprocess, the still liquid layer is subject to whirling effects oragitations of substance, which are caused by changes in the surfacetension of the layer in the course of drying. Evaporation of the solventgives rise to two factors which mutually intensify each other and raisethe surface tension of the drying layer at its interface to the ambientair. On the one hand, the temperature drop leads to a rise in surfacetension of the order of 0.1 mN/m/°C.; on the other hand, surface tensionis additionally augmented by the increase in concentration of thefilm-forming substances contained in the solution.

Emanating from numerous small swelling points in the underlying layer ofless concentrated solution, material of higher temperature and lowersurface tension, forces its way to the surface. As a result,corresponding centers are formed on the surface and from these centers,the liquid rising from below spreads, until the fronts of the spreadingwaves of adjacent centers meet. Due to a deviation of the liquidagitation into the interior of the layer, turbulences are produced.

This phenomenon is, to a particularly high degree, encountered in themanufacture of light-sensitive printing plates, especially ofplanographic printing plates, where relatively highly diluted solutionsof low viscosity are frequently used. Layers which are cloudy and havenon-uniform thicknesses and colorations are often obtained, and suchirregularities in layer-thickness have a negative effect on the printingresult, particularly in plates for screenless offset printing. Here, thesurface structure of the plate is reproduced on the impression in graytone steps, i.e., uniform gray areas are not printed.

From Research Disclosure (1976) 145, page 15, No. 14522, it is known toadd a combination of a non-ionic surfactant, i.e., isononyl phenoxydecaglycidol, and an anionic surfactant, i.e., an ammonium salt ofsulfated nonyl phenoxy poly(ethyleneoxy)ethanol, to lithographic layersto improve the coatability of the coating solution and to ensure goodinking properties. Other, less active surfactant combinations which arementioned, are the alkyl aryl polyglycol ether carboxylic acidmonoethanolamine salt or polyoxyethylene polymethylsiloxane. Accordingto this description, one surfactant alone is not sufficient to yield thedesired properties; the non-ionic surfactant, if used alone, causes adeterioration of ink receptivity and scumming of the background.

German Offenlegungsschrift No. 29 14 558 discloses a coating process inwhich the uniformity of the light-sensitive layers on planographicprinting plates is improved by adding to the coating solution a polymerwhich has a molecular weight of at least 10,000 and which contains atleast one fluoroalkyl group. As stated in the specification, theaddition of these polymeric compounds results in a more uniform layerthickness. Although it is mentioned in the description that a number ofsolvents can be used, individually or in mixtures, for the preparationof the coating solutions, solvent mixtures exclusively are employed inthe examples, and in each case, the mixture contains one low-boiling andone high-boiling solvent.

The use of high-molecular weight compounds with fluorinated side chainshas, in addition, the disadvantage that these polymers are no longersoluble in all customary solvents, so that the choice of a solvent islimited.

From U.S. Pat. No. 3,779,774 it is known to add particular polysiloxaneswhich contain oxyalkylene groups and, preferably, hydroxy groups andamino groups, to the light-sensitive layers of vesicular films toimprove the resolution and sensitivity of the films by a formation ofsmaller bubbles. An influence of these additions on the coating qualityis not mentioned. As is stated in the publication, saponin or similarsurfactants were already earlier used for the same purpose.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide alight-sensitive copying material which can be coated easily withlight-sensitive layers of high quality and uniformity.

It is also an object of the invention to provide a light-sensitivecopying material which can be produced with a great number of solventsand which, if desired, can be prepared from a solution which comprisesonly one solvent.

A further object of the invention is to provide an improved process forproducing a light-sensitive copying material according to the invention.

In accomplishing these and other objects, there has been provided inaccordance with one aspect of the present invention a light-sensitivecopying material, comprising a support sheet; and a light-sensitivelayer comprising a material which undergoes a change in solubility in adeveloper upon exposure to actinic light, and from about 0.01 to 10percent by weight of a surfactant comprised of a surface-activepolysiloxane containing dialkylsiloxane units and oxyalkylene units.Preferably, the surface-active polysiloxane is contained in thelight-sensitive layer in a quantity sufficient to reduce in a linearmanner by about 40 to 75 percent the spreading capacity on the supportsheet of a coating solution containing the layer components and in aquantity sufficient to reduce the surface tension of the light-sensitivelayer toward water by 2 to 12 mN/m, as compared with a layer which isfree of the polysiloxane.

In accordance with another aspect of the present invention, there hasbeen provided a process for producing a light-sensitive copyingmaterial, comprising the steps of coating a support sheet with asolution comprising at least one light-sensitive component and fromabout 0.005 to 1 percent of a surfactant dissolved in a solvent, to forma thin layer of the solution on the support, wherein the surfactantcomprises a surface-active polysiloxane containing dialkylsiloxane unitsand oxyalkylene units; and drying the thin layer to remove the solventtherefrom to produce a light-sensitive layer on the support layer.

Further objects, features and advantages of the present invention willbecome apparent from the detailed description of preferred embodimentswhich follows.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The invention is based on a light-sensitive copying material comprisinga support and a light-sensitive layer which, upon exposure to actiniclight, undergoes a change of solubility in a developer and whichcontains a surfactant. The copying material of the invention ischaracterized in that the layer contains as the surfactant asurface-active polysiloxane which comprises dialkylsiloxane units andoxyalkylene units and is present in a quantity ranging from about 0.01to 10 percent by weight.

According to the invention, a process is also provided for coating asupport with a light-sensitive copying layer. The process comprisesdissolving the layer components, together with a surfactant, in asolvent, applying the solution to the support to form a thin, uniformlayer thereon and drying the layer by evaporation of the solvent,preferably at elevated temperature. The process has the feature thatfrom about 0.005 to 1 percent by weight, preferably from about 0.01 to0.05 percent by weight of a surface-active polysiloxane which iscomposed of dialkylsiloxane units and oxyalkylene units is added to thecoating solution.

The surface-active polysiloxanes which are added to the coating solutionaccording to the invention, are preferably comprised of units of theformulae: ##STR1## in which

m and n are integers ranging from 1 to 4, preferably 1 or 2,

r is an integer ranging from 2 to 5, preferably 2 or 3,

x is an integer ranging from about 10 to 100, preferably from about 20to 60, and

y is an integer ranging from about 25 to 350, preferably from about 50to 200.

The molecular weights of the surface-active polysiloxanes are in therange from about 1,800 to 40,000, preferably from about 3,500 to 16,000.

The action of the surfactants depends essentially on the solvent used,whereas the chemical nature and composition of the dissolved ordispersed components of the layer, particularly of the light-sensitivesubstances, is of minor importance.

For each layer composition, a suitable solvent can easily be determinedby preliminary tests. The added surfactant, if used in concentrationswithin the above-specified ranges, reduces the surface tension of therespective coating solution toward air by 1 to 6 mN/m. The surfacetension of the dry layer toward water is reduced by 2 to 10, preferably5 to 8 mN/m, by the surfactant addition.

Due to their strong surface-active effect, the surfactants concentrateat the interfaces of the coating solution. Especially in the case ofrough support surfaces which have a very high surface tension, thisleads, surprisingly, to a reduction of the spreading tendency of thesolution. It is assumed that also the spreading of liquid phases whichare in their early drying stages and have low concentrations on filmphases in advanced drying stages is largely suppressed by theconcentration of the surfactants at the interfaces. Agitations of theliquid film during drying are thus probably strongly inhibited andlayers are produced which have an improved uniformity after drying.

Only few of the numerous well-known surfactants, however, show thispositive effect. It is considered decisive for the action of thesurfactants described in the present application that siloxane units andoxyalkylene units are combined in one molecule. Although thesesurfactants, on account of their pronounced surface-active propertiesand relatively low molecular weights, are concentrated to a considerabledegree at the interfaces of the layer being formed, they impair neitherthe image differentiation upon development or the oleophilic propertiesof the image areas which are insoluble in the developer, nor thehydrophilic properties of the decoated areas of the support surface orthe print run of the printing form obtained.

The spreading capacity of the coating solution has proved to be afurther measure of the suitability of a surfactant and a means ofdetermining the appropriate range of concentration of the surfactant inthe solution. The spreading capacity is easily determined by applying adefined quantity of the solution to a specific support and measuring thediameter of the wetting zone after drying at room temperature. Thesupport consists, appropriately, of a material of very uniform surfaceroughness, for example, electrolytically roughened aluminum, because onsuch a material the effects which may be observed appear most clearlyand are reproducible with the highest degree of certainty.

The values for the spread-inhibiting action of a surfactant, which aredetermined on such a support material represent good approximate valueswhich may be applied to the behavior of this surfactant on an entirelydifferent support material (for example, polyester film).

By adding the above-defined surfactants to the coating solution, thespreading capacity of the solution is intended to be reduced by about 40to 75 percent, preferably by about 50 to 70 percent, relative to thediameter of the wetting zone.

When coating customary support materials (for example, aluminum)cloud-free, optically homogeneous copying layers of uniform colorationand layer thickness are obtained, even if very small amounts of thesurfactants (less than about 0.1 percent) are added to the coatingsolution, which further contains light-sensitive or photoconductivesubstances, and optionally binders, dyes and other usually employedcomponents, dissolved in a conventional mixture of a high-boiling and alow-boiling solvent, for example, ethylene glycol monomethylether/tetrahydrofuran or ethylene glycol monomethyl ether/butylacetate/tetrahydrofuran. In view of their coating quality, the copyinglayers thus produced are superior to the standard which is presentlynormal and achievable, in particular in presensitized planographicprinting plates.

Suitable solvents for the coating solutions are, for example, the knownglycol derivatives, amides, chlorinated hydrocarbons, and ketones, forexample, ethylene glycol monomethyl ether, ethylene glycol monoethylether, ethylene glycol monoisopropyl ether, dimethyl formamide,butyrolactone, methylene dichloride, dichloroethane or butanone. It ispossible to blend the solvents mentioned with other solvents in whichthe substances to be dissolved are not necessarily soluble; among thesenumber, primarily, ethers and esters, such as dioxane, tetrahydrofuran,butyl acetate and ethylene glycol methyl ether acetate.

In combination with the surface-active polysiloxane glycol monoalkylethers, for example, ethylene glycol monomethyl ether, glycol etheresters, for example, ethylene glycol methyl ether acetate or chlorinatedhydrocarbons, for example, dichloroethane, have proved to beparticularly suitable as components of good dissolving power.

In ketones, for example, cyclohexanone or butanone, which are used assolvents, the levelling action is reduced, and the range for theaddition of the polysiloxane is limited. In cyclic ethers, for example,tetrahydrofuran, esters, for example, butyl acetate, and in alcohols,for example, ethanol, the influence of the surface-active polysiloxanesis negligible.

By adding the specified surfactants to the coating solution it is,surprisingly, rendered possible to do with only one solvent and toobtain layers which are of better quality than those which could, up tonow, be prepared by means of the above-described solvent combinations.It is obvious that reclaiming and purifying a single solvent isconsiderably easier technologically than the corresponding processing ofsolvent mixtures. In particular, it is much easier to remove arelatively high-boiling solvent from the exhaust air than a mixtureconsisting of high-boiling and low-boiling constituents.

As the solvents which are used alone, the above-mentionedgood-dissolving compounds, particularly the glycol monoethers, aresuitable. Due to their good solvent power for various substances, theymay be universally employed for copying layers of different types, forexample, layers based on negative-acting or positive-acting diazocompounds, photopolymerizable layers, photoconductive layers, etc. It isalso possible to advantageously coat widely different support materialsaccording to the process of the present invention.

Apart from the above-stated, generally valid advantages which areobtained in the production of printing plates when one solvent only isemployed, it has surprisingly been found to be additionally possible, byusing particular solvents, such as glycol monoethers, e.g., ethyleneglycol monomethyl ether, as the only solvent of coating solutions forthe manufacture of presensitized printing plates, particularly ofplanographic printing plates, to achieve advantages in the copyingbehavior of such plates, in comparison with materials produced fromsolvent mixtures, but without surfactant addition.

Depending on the kind of the light-sensitive system, the followingadvantages appear: better contrast upon exposure, shorter developingtime, reduced consumption of developer, improved developer resistance,higher light-sensitivity, higher resolution and/or reduced tendency tohalations. In a particular type of printing plate, these advantages areusually not all encountered at the same time, and they are more or lesspronounced according to the plate type concerned.

Differences in the printing behavior, for example, ink receptivity,water acceptance and length of print run, are usually not observedbetween planographic printing plates coated from glycol ethers with anaddition of the surface-active polysiloxanes and others which werecoated from solvent mixtures without surfactant addition.

The light-sensitive layers which can be applied to supports using thesurfactants may vary widely in nature and composition. The term"light-sensitive layer" as herein used shall be understood as includinglayers having a light-sensitivity which is only activated by apretreatment, for example, by application of an electrostatic charge,i.e., electrophotographic layers.

Similarly, layers are herein incorporated which are prepared in twostages, for example, resin or binder layers which are renderedlight-sensitive only after subsequently soaking or impregnating with asolution of a light-sensitive substance, for example, a dichromate or adiazo compound. In that case, the surfactant which is added according tothe invention is used in the first stage, i.e., in the actual productionof the layer. In addition, layers which are industrially manufactured,such as in presensitized printing plates, and layers which are appliedby the user of the light-sensitive material, i.e., photoresist layers orthe layers in wipe-on printing plates, are also included. The inventionfurther covers reprographic copying layers which are insensitive tovisible or long-wave ultraviolet light, but are sensitive to high-energyradiation, such as electron or laser radiation. In principle, theinvention is applicable to any reprographic layers in which it isimportant to have a uniform, homogeneous structure and layer thickness.

The light-sensitive systems concerned include all those whereinsolubility in a developer is changed upon exposure or irradiation,respectively, that is to say, mixtures which are hardened by exposure tolight (negative) and mixtures which are rendered soluble by exposure tolight (positive). Also suitable are those electrophotographic systems,with the aid of which a charge image, optionally a toner image, is firstproduced and is then used to form a relief image, for example, for theproduction of a printing form, by transferring the charge image or tonerimage or by decoating the areas of the plate which are not covered bythe toner image.

Suitable light-sensitive mixtures are, above all, those which are basedon positive-acting or negative-acting diazo compounds, for example,based on o-quinone diazides or diazonium salt polycondensation products.These mixtures often contain film-forming resins or binders. GermanOffenlegungsschriften No. 23 31 377, No. 25 47 905 and No. 28 28 037disclose suitable positive-acting layers of that kind, whilenegative-acting layers of the type specified are described, for example,in U.S. Pat. No. 3,867,147. The disclosure of each of these publisheddocuments is hereby incorporated by reference.

Also suitable are positive-acting mixtures based on compounds whichcontain acid-cleavable orthocarboxylic acid groups or acetal groups andphotolytic acid donors, as described, for example, in German Patent No.26 10 842 and in German Offenlegungsschriften No. 27 18 254 and No. 2928 636, the disclosures of which are also incorporated herein byreference.

It is further possible to employ photopolymerizable mixtures composed ofethylenically unsaturated polymerizable compounds, photoinitiators and,optionally, polymeric binders, for example, as described in U.S. Pat.No. 2,760,863, German Pat. No. 20 27 467 and GermanOffenlegungsschriften No. 20 64 079, No. 23 63 806 and No. 28 22 190.These disclosures are also incorporated herein by reference.

As has already been mentioned above, photoconductive materialscomprising inorganic or organic photoconductors and, if appropriate,polymeric binders can also be used, for example, as disclosed in GermanPat. No. 23 22 047, No. 15 22 497 and No. 18 11 209 and in GermanAuslegeschrift No. 27 26 116, which are also incorporated herein byreference.

Suitable supports are those which are known in the art, i.e., metals,for example, aluminum, copper, chromium-plated copper or brass, steeland the like, plastic sheets, for example, consisting of celluloseacetate or polyethylene terephthalate, copper-clad molded-resin platesetc.

Coating can be accomplished by roller application, dip coating, slot-diecoating, casting, etc. The levelling effect of the added surfactants isonly slightly or even not at all influenced by the method used to applythe coating solution.

The desired relief image is produced on the coated copying materialsobtained according to the process of the present invention, in theconventional manner, by image-wise exposing or irradiating and washingout the non-image areas with a developer, preferably an aqueousdeveloper solution. In the developing procedure, the surfactantscontained in the layer are, together with the soluble layer areas,completely removed from the non-image areas, so that the support whichhas been uncovered in these areas does not show any scumming propensity.

In the preceding description and in the examples which follow, referenceis mainly made to the manufacture of planographic printing masters,which is the most important field of application for the process andmaterial according to the invention. The invention is advantageouslyalso used in the production of other types of printing plates, such asletterpress or intaglio printing plates or in the manufacture ofphotoresists and other reprographic materials, where it is important toapply light-sensitive or radiation-sensitive layers of uniform thicknessand unchanging quality.

Preferred embodiments of the invention are explained in the followingexamples. In the examples, parts by weight (p.b.w.) and parts by volume(p.b.v.) have the same relationship as the g to the cm³. Unlessotherwise specified, percentages and weight ratios are to be understoodas denoting units by weight. The examples are intended to beillustrative only and in no sense limiting.

EXAMPLE 1

An electrolytically roughened and anodized aluminum web was coated bymeans of a slot die with the following solution:

6.6 p.b.w. of a cresol formaldehyde novolak having a softening rangefrom 105° to 120° C., according to DIN 53 181,

1.1 p.b.w. of the 4-(2-phenyl-prop-2-yl)-phenylester ofnaphthoquinone-(1,2)-diazide-(2)-sulfonic acid-(4),

0.6 p.b.w. of2,2'-bis-[naphthoquinone-(1,2)-diazide-(2)-sulfonyloxy-(5)]-dinaphthyl-(1,1')-methane,

0.24 p.b.w. of naphthoquinone-(1,2)-diazide-(2)sulfochloride-(4),

0.08 p.b.w. of Crystal Violet,

0.02 p.b.w. of a copolymer of dimethyl dichlorosilane, ethylene oxideand propylene oxide, having a viscosity of 9 cm² /second at 25° C. and asurface tension of 18 mN/m, and

91.36 p.b.w. of a solvent mixture composed of 4 p.b.v. of ethyleneglycol monomethyl ether, 5 p.b.v. of tetrahydrofuran and 1 p.b.v. ofbutyl acetate.

The coated web was dried by passing it through a drying channel attemperatures up to 120° C.

The resulting layer had an entirely uniform appearance, free from cloudyirregularities. Small coating defects could thus easily be detectedwithin the scope of a prolonged production cycle.

The printing plates were exposed under a positive original and developedusing a developer of the following composition:

5.3 p.b.w. of sodium metasilicate ×9H₂ O,

3.4 p.b.w. of trisodium phosphate ×12H₂ O,

0.3 p.b.w. of sodium dihydrogen phosphate (anhydrous) and

91.0 p.b.w. of water.

The printing forms obtained did not show any copying or printingdefects.

In the same manner as described above, printing plates were produced bycoating with a solution which did not contain any surface-activepolysiloxane, but which, otherwise, had the same composition as theabove-described coating solution.

In this case, the copying layers had an irregular appearance and anon-uniform coloration. They exhibited lighter and darker zones whichwere approximately equally distributed with respect to size and numberand were more or less strongly elongated in the coating direction. On anaverage, about 3 to 5 light and dark zones were perceivable in each cm²of the surface. The appearance of such layers is generally called"cloudy".

The printing forms prepared as described in the paragraph before lasthad the same copying and printing behavior as the printing formsprepared according to the present invention.

EXAMPLE 2

The procedure of Example 1 was repeated; however, in the coatingsolution the above-specified solvent mixture was replaced by the samequantity of ethylene glycol monomethyl ether as the only solvent. Thecoating quality obtained was the same as in Example 1.

Upon exposure, the printing plates thus produced showed a markedlyhigher image contrast, a slightly increased sensitivity to light and areduced tendency to halations, as against the comparative platesdescribed in Example 1, which had been prepared without an addition of asurface-active polysiloxane, but with a solvent mixture.

When developing the exposed printing plates with a 20 percent reducedquantity of developer, the developing time could be shortened by 14percent, as compared to the above-mentioned comparative plates.

With respect to ink receptivity, water acceptance and print run, nodifference to the comparative plate could be observed.

If, in lieu of ethylene glycol monomethyl ether, the same quantity ofcyclohexanone or methyl ethyl ketone was used as the only solvent,essentially the same results were obtained as far as the coating qualityand the copying and printing behavior of the plates were concerned. Ifthe surfactant was entirely omitted in an otherwise identical coatingsolution, an extremely cloudy, irregular copying layer of unacceptablecoating quality resulted.

EXAMPLE 3

A solution of

1.50 p.b.w. of the ester of 1 mole of2,4-dihydroxy-3,5-dibromo-benzophenone and 2 moles ofnaphthoquinone-(1,2)-diazide-(2)-5-sulfonic acid,

5.20 p.b.w. of a phenol formaldehyde novolak comprising 14 percent ofphenolic OH groups and having a softening range between 110° and 120°C., according to DIN 53 181,

0.20 p.b.w. of polyvinyl butyral,

0.15 p.b.w. of Crystal Violet,

0.08 p.b.w. of Sudan Yellow GGN (Colour Index 11 021),

0.60 p.b.w. of tris-(β-chloroethyl)-phosphate and

0.02 p.b.w. of the surfactant specified in Example 1 in

92.25 p.b.w. of a solvent mixture composed of 40 p.b.v. of ethyleneglycol monomethyl ether and 50 p.b.v. of tetrahydrofuran

was applied to an aluminum foil which had been roughened by brushingwith steel brushes, and the coating was then dried in a drying channelat temperatures up to 110° C.

The positive-acting, presensitized planographic printing plates thusprepared had a very uniform light-sensitive layer. The plates exhibitedperfect copying and printing properties.

EXAMPLE 4

A presensitized printing plate was prepared as in Example 3, by coatinga support, however, this time the solvent mixture was replaced by thesame quantity of ethylene glycol monomethyl ether as the only solvent.The layer on the resulting printing plate corresponded in quality to thelayer obtained in Example 3.

The printing plate thus prepared showed the advantages of an easierdevelopability, a better developer resistance of the image areas, and areduced tendency to halations, as compared to a plate which had beenproduced according to Example 3, but without addition of a surfactant.

The printing results corresponded approximately to those obtained withthe comparative plate.

EXAMPLE 5

An electrolytically roughened and anodized aluminum plate was immersedfor 1 minute in water at 60° C. in which 0.3 percent by weight ofpolyvinyl phosphonic acid had been dissolved; it was then rinsed anddried, then coated with the following solution and dried again:

0.7 p.b.w. of the polycondensation product of 1 mole of3-methoxy-diphenylamine-4-diazonium sulfate and 1 mole of4,4'-bis-methoxymethyl-diphenyl ether, precipitated as the mesitylenesulfonate,

3.4 p.b.w. of 85 percent phosphoric acid,

3.0 p.b.w. of a modified epoxy resin, obtained by reacting 50 g of anepoxy resin having a molecular weight below 1,000 with 12.8 g of benzoicacid in ethylene glycol monomethyl ether, in the presence of benzyltrimethyl ammonium hydroxide,

0.44 p.b.w. of finely ground Heliogen Blue G (Colour Index 74 100),

0.02 p.b.w. of a copolymer of dimethyl dichlorosilane and ethyleneoxide, comprising about 15 to 25 siloxane units and 50 to 70 oxyethyleneunits in each molecule and having an average molecular weight of 5,000,

62.0 p.b.w. of ethylene glycol monomethyl ether,

30.6 p.b.w. of tetrahydrofuran and

8.0 p.b.w. of ethylene glycol methyl ether acetate.

The resulting copying layer showed a considerably improved evenness anda more uniform coloration than a copying layer which had been preparedwithout addition of the surfactant, but which had, otherwise, the samecomposition. The printing plate had the same copying and printingproperties as the comparative plate. The two plates were developed witha solution of

2.8 p.b.w. of Na₂ SO₄ ×10H₂ O,

2.8 p.b.w. of MgSO₄ ×7H₂ O,

0.9 p.b.w. of orthophosphoric acid (85 percent),

0.08 p.b.w. of phosphorous acid,

1.6 p.b.w. of a non-ionic surfactant,

10.0 p.b.w. of benzyl alcohol,

20.0 p.b.w. of n-propanol,

60.0 p.b.w. of water.

EXAMPLE 6

The procedure followed was the same as in Example 5 with the exceptionthat for coating, ethylene glycol monomethyl ether was used as the onlysolvent, instead of the solvent mixture.

The copying layer obtained showed a high degree of homogeneity and auniform layer thickness and coloration. Compared with a layer which hadbeen prepared from the solvent mixture of Example 5, without addition ofa surfactant, this layer had a higher light sensitivity and an improvedresolution.

The developing time required for the layer produced with addition of asurfactant was reduced by 30 percent, compared with the developing timerequired for the comparative plate. The two plates showed an identicalprinting behavior.

EXAMPLE 7

An aluminum support which had been roughened by brushing with an aqueousabrasive suspension and then treated with an aqueous solution ofpolyvinyl phosphonic acid was coated with a solution of the followingcomposition:

0.6 p.b.w. of the diazonium salt condensation product specified inExample 5,

0.06 p.b.w. of phosphoric acid (85 percent),

1.7 p.b.w. of polyvinyl formal (molecular weight 30,000, 7 percenthydroxy groups, 20 to 27 percent acetate groups),

2.7 p.b.w. of a dispersion of a copper phthalocyanine pigment (ColourIndex 74 160) in ethylene glycol methyl ether acetate, 0.02 p.b.w. ofthe surfactant specified in Example 5 and

95 p.b.w. of ethylene glycol monomethyl ether.

The copying layer exhibited an outstanding uniformity.

After imagewise exposure, the layer could be more easily developed thana corresponding layer which, however, had been prepared without additionof a surfactant, from a solvent mixture of 50 parts by weight ofethylene glycol monomethyl ether, 40 parts by weight of tetrahydrofuranand 10 parts by weight of butyl acetate. The layer was developed withthe following solution:

5.7 p.b.w. of MgSO₄ ×7H₂ O,

25.5 p.b.w. of n-propanol,

1.1 p.b.w. of ethylene glycol mono-n-butyl-ester,

0.7 p.b.w. of alkyl-polyethoxy-ethanol and

67.0 p.b.w. of water.

EXAMPLE 8

The coating solution described in Example 7 was applied to anelectrolytically roughened and anodized aluminum support which had beenafter-treated with an aqueous solution of polyvinyl phosphonic acid.

The presensitized planographic printing plate obtained after drying ofthe coating, exhibited a high coating quality and, in addition, aslightly higher sensitivity to light; it required a noticeably shorterdeveloping time, yielding a more complete development of the fine lineareas, as against a plate which had been coated from a solvent mixturecomposed of 50 p.b.w. of ethylene glycol monomethyl ether, 40 p.b.w. oftetrahydrofuran and 10 p.b.w. of butyl acetate, however, withoutsurfactant addition.

If, in this example, ethylene glycol monomethyl ether is replaced bydichloroethane as the only solvent, basically the same results areachieved.

EXAMPLE 9

An electrolytically roughened and anodized aluminum plate which had beenafter-treated with an aqueous solution of polyvinyl phosphonic acid wascoated with the following solution:

1 p.b.w. of the diazonium compound specified in Example 5,

0.5 p.b.w. of the polyvinylformal of Example 7,

0.03 p.b.w. of a copolymer of dimethyl dichlorosilane and propyleneoxide having an average molecular weight of 7,000,

98.5 p.b.w. of ethylene glycol monomethyl ether.

The presensitized planographic printing plate obtained after drying wasimagewise irradiated by means of an argon laser at 10 watts capacity.

The following solution was used for developing:

6.0 p.b.w. of magnesium sulfate,

0.7 p.b.w. of fatty alcohol polyglycol ether,

65.0 p.b.w. of water and

32.0 p.b.w. of n-propanol.

As a comparison, the same layer components were applied to the supportfrom a solvent mixture comprising 40 parts by volume of tetrahydrofuranand 60 parts by volume of ethylene glycol monomethyl ether, however,without addition of the polysiloxane.

The layer on this plate was of a considerably poorer quality andrequired a noticeably longer exposure time.

If coating was effected from ethylene glycol monomethyl ether as theonly solvent and without addition of a surfactant, an extremely cloudylayer showing considerable variations in layer density was obtained.

EXAMPLE 10

A solution of

10 p.b.w. of 2,5-bis-(4'-diethylaminophenyl)-1,3,4-oxadiazole,

10 p.b.w. of a copolymer of styrene and maleic anhydride having anaverage molecular weight of 20,000 and an acid number of 180,

0.02 p.b.w. of Rhodamine FB (Colour Index 45 170) and

0.02 p.b.w. of the surfactant used in Example 5 in

300 p.b.w. of ethylene glycol monomethyl ether

was applied to an aluminum foil which had been electrolyticallyroughened, anodized and treated with polyvinyl phosphonic acid. A veryuniform photoconductor layer without any visible structures had formedafter evaporation of the solvent.

The layer was negatively charged in the dark to about 400 V by means ofa corona. The charged plate was then imagewise exposed in a reprocameraand developed using an electrophotographic suspension developer obtainedby dispersing 3.0 g of magnesium sulfate in a solution of 7.5 g of apentaerythritol resin ester in 1,200 ml of an isoparaffin mixture havinga boiling range from 185° to 210° C. Any excess developer liquid wasremoved and the plate was dipped for 60 seconds into a solution of

35 p.b.w. of sodium metasilicate ×9H₂ O.

140 p.b.v. of glycerol,

550 p.b.v. of ethylene glycol and

140 p.b.v. of ethanol.

It was then rinsed with a strong jet of water so that any parts of thephotoconductor layer which were not covered by the toner were removed.The plate was then ready for printing.

Since the surfactant used was a non-ionogenic substance, thechargeability of the electrophotographic layer and the leakage of thecharge upon exposure remained uninfluenced.

As far as processing characteristics and printing behavior wereconcerned, the plate which had an improved coating quality, did notdiffer from a comparative plate which had been coated from a solventmixture of 3 parts by weight of tetrahydrofuran, 2 parts by weight ofethylene glycol monomethyl ether and 1 part by weight of butyl acetate,without addition of a surfactant.

Another plate which had been prepared in the same way, but withoutaddition of a surfactant and with ethylene glycol monomethyl ether asthe only solvent showed a wrinkly structure which was perceivable evento the naked eye.

EXAMPLE 11

A solution of

10 p.b.w. of the diazonium salt condensation product specified inExample 5,

4 p.b.w. of the azo dye composed of 2,4-dinitro-6-chlorobenzenediazonium salt and2-methoxy-5-acetylamino-N-hydroxyethyl-N-cyanoethylaniline,

1 p.b.w. of metanil yellow (Colour Index 13 065),

2 p.b.w. of phosphoric acid (85 percent) and

0.2 p.b.w. of the surfactant mentioned in Example 5 in

970 p.b.w. of ethylene glycol monomethyl ether

was applied to an electrolytically roughened and anodized aluminum foil.A cloud-free, uniform layer was obtained.

EXAMPLE 12

A solution of

28 p.b.w. of a 50 percent strength aqueous dispersion of a terpolymer ofvinyl acetate, ethylene and vinyl chloride,

4 p.b.w. of a 32 percent strength dispersion of copper phthalocyanine(Colour Index 74 160) in a 3:1 ethylene glycol/water mixture,

4 p.b.w. of the diazonium salt condensation product specified in Example5,

0.3 p.b.w. of metanil yellow,

0.2 p.b.w. of phosphoric acid (85 percent), and

0.2 p.b.w. of a copolymer containing in its molecule 25 to 40 dimethylsiloxane units, 120 to 150 oxyethylene units and 80 to 100 oxypropyleneunits and having an average molecular weight of 13,500 in

970 p.b.w. of ethylene glycol monomethyl ether,

was applied to an electrolytically roughened and anodized aluminumplate. The copying layer obtained was cloud-free. If however, thesurfactant was omitted in the coating solution, the resulting layer wasextremely cloudy and had a non-uniform thickness.

EXAMPLE 13

A solution of

14 p.b.w. of a copolymer of methyl methacrylate and methacrylic acidhaving an average molecular weight of 40,000 and an acid number rangingbetween 90 and 115,

14 p.b.w. of 1,1,1-trimethylolethane triacrylate,

2 p.b.w. of 1,6-bis-hydroxyethoxy-hexane,

0.5 p.b.w. of 9-(p-hydroxy-phenyl)-acridine and

0.02 p.b.w. of the surfactant used in Example 5 in

130 p.b.w. of ethylene glycol monoethyl ether

was applied to an electrolytically roughened and anodized aluminum foiland dried thereon.

The photopolymerizable copying layer obtained was free of clouds andcompletely uniform.

The layer was exposed for 1 minute under an original, using a 5 kW xenonpoint lamp. It was then wiped over for 1 minute with a developercomposed of

15 p.b.w. of sodium metasilicate×9 H₂ O,

3 p.b.w. of polyglycol 6000,

0.6 p.b.w. of levulinic acid and

0.3 p.b.w. of strontium hydroxide×8 H₂ O in

1000 p.b.w. of water,

so that the unexposed layer areas were removed. Developing was followedby rinsing with water, fixing with 1 percent strength phosphoric acidand inking with black greasy ink. When the same coating composition,prepared, however, without addition of a surfactant, was applied fromethylene glycol monomethyl ether as the only solvent, the resultingcopying layer was cloudy and non-uniform.

Similarly, a cloudy copying layer was obtained, when a mixture of 70parts by volume of ethylene glycol monoethyl ether and 30 parts byvolume of ethylene glycol monobutyl ether was used as the coatingsolvent. This layer required a longer exposure time compared with thelayer which contained the surfactant.

EXAMPLE 14

A solution of

25 p.b.w. of bis-(5-ethyl-5-butyl-1,3-dioxane-2-yl)-ether of2-ethyl-2-butyl-1,3-propane-diol,

71 p.b.w. of the cresol formaldehyde novolak used in Example 1,

3 p.b.w. of 2-(acenaphth-5-yl)-4,6-bis-trichloromethyl-s-triazine,

0.7 p.b.w. of Crystal Violet base and

0.2 p.b.w. of the surfactant specified in Example 5 in

900 p.b.w. of ethylene glycol monomethyl ether

was applied to an electrolytically roughened and anodized aluminum foiland dried. The positive-acting copying layer obtained was free of cloudsand showed a high coating quality.

The plate was exposed in the customary manner under an original and wasthen developed using the developer mentioned in Example 1.

Similar results were obtained, when the specified orthoester derivativewas replaced by other orthocarboxylic acid esters, for example, asdescribed in German Offenlegungsschrift No. 26 10 842 or whenpolyacetals were used, as described in German Offenlegungsschrift No. 2718 254.

EXAMPLE 15

A solution of

2 p.b.w. of the ester of 1 mole of 2,3,4-trihydroxybenzophenone and 3moles of naphthoquinone-(1,2)-diazide-(2)-5-sulfonic acid,

3 p.b.w. of Zapon Fast Blue HFL (Colour Index 74 350),

1 p.b.w. of Sudan Blue II (Colour Index 61554 S) and

0.02 p.b.w. of the surfactant specified in Example 5 in

94 p.b.w. of a mixture composed of 30 parts by volume of ethylene glycolmonomethyl ether, 20 parts by volume of methyl ethyl ketone and 10 partsby volume of butyl acetate,

was applied to a polyester film. The resulting coating on the film wascompletely free of clouds and exhibited a uniform coloration. This filmcould be used as a color proofing film.

If, however, a corresponding coating solution without addition of asurfactant was applied to the same support, the resulting layer showedextreme variations of color density.

EXAMPLE 16

For the preparation of a positive-acting dry resist, a solution wasprepared from

11.15 p.b.w. of the novolak according to Example 1,

2.79 p.b.w. of a vinyl acetate/crotonic acid copolymer (95:5) having amolecular weight of 100,000,

4.18 p.b.w. of a copolymer comprising 5:1:2 parts ofn-hexylmethacrylate/methyl methacrylate/methacrylic acid and having anacid number of 158,

2.79 p.b.w. of an epoxy resin having an epoxy equivalent weight of 190,

2.32 p.b.w. of the bis-naphthoquinone-(1,2)-diazide-(2)-sulfonicacid-(5)-ester of 4,4-bis-(4-hydroxy-phenyl)-valeric acid-3-methoxybutylester,

0.45 p.b.w. of naphthoquinone-(1,2)-diazide-(2)-sulfochloride-(4),

0.02 p.b.w. of the surfactant described in Example 1 and

0.06 p.b.w. of Crystal Violet in

48.34 p.b.w. of ethylene glycol monoethyl ether and

27.90 p.b.w. of methyl ethyl ketone.

This solution was applied to an about 25 μm thick polyester film whichhad been pretreated with an aqueous solution of 10 percent oftrichloroacetic acid, 1 percent of polyvinyl alcohol and 0.1 percent ofa surfactant, and was then dried. The coating obtained was very uniform.

The above-described solvent mixture was replaced by 76.24 parts byweight of ethylene glycol monoethyl ether, without thereby affecting thecoating quality.

The about 20 μm thick resist layer was then provided with a polyethylenecover film to protect it from dust and scratches.

For the manufacture of circuit boards, the cover film was peeled offfrom the positive-acting dry resist film and then a commercial laminatorwas used to apply the film to a cleaned, about 35 μm thick copper foilwhich had been laminated to a support consisting of an insulatingmaterial. After peeling off the support film, if appropriate, dryingagain, exposing for about 3 minutes with the aid of a conventionalexposure apparatus and spray-developing for about 2 minutes with adeveloper of the following composition

0.6 p.b.w. of NaOH,

0.5 p.b.w. of Na₂ SiO₃ ×5 H₂ O,

1.0 p.b.w. of n-butanol and

97.9 p.b.w. of water

an excellent resist layer in imagewise distribution was obtained. It wasnot only resistant to the conditions prevailing in etching processes,for example, using FeCl₃, but also to the electroplating solutions usedin the manufacture of through-hole printed circuits, in particular whensuccessively electroplating with copper, nickel and gold.

EXAMPLE 17

A solution of

3.0 p.b.w. of the bis-naphthoquinone-(1,2)-diazide-(2)-sulfonicacid-(5)-ester of 4,4-bis-(4-hydroxy-phenyl)-valeric acid methyl ester,

21.0 p.b.w. of the phenol formaldehyde novolak according to Example 3,

3.0 p.b.w. of the vinyl acetate/crotonic acid copolymer of Example 16,

3.0 p.b.w. of an epoxy resin (epoxy equivalent weight about 450),

0.4 p.b.w. of Sudan Blue II (Colour Index Solvent Blue 35) and

0.02 p.b.w. of the surfactant specified in Example 1 in

49.6 p.b.w. of ethylene glycol monoethyl ether acetate,

10.0 p.b.w. of ethylene glycol monoethyl ether and

10.0 p.b.w. of butyl acetate or in

69.6 p.b.w. of ethylene glycol monoethyl ether

resulted in a positive-acting photoresist composition which was suitablefor the manufacture of circuit boards, gravure printing cylinders andfor use in chemical milling or in nickel-type stencils.

EXAMPLE 18

A solution of

2.8 p.b.w. of a terpolymer of methyl methacrylate, n-hexyl methacrylateand methacrylic acid (25:125:30) having an acid number of 202,

2.8 p.b.w. of the reaction product obtained by reacting 1 mole of2,2,4-trimethyl-hexamethylene diisocyanate with 2 moles of hydroxyethylmethacrylate,

0.005 p.b.w. of the surfactant specified in Example 1,

0.5 p.b.w. of diethylene glycol monohexyl ether,

0.03 p.b.w. of tris-[4-(3-methyl-phenylamino)-phenyl]methyl acetate and

0.025 p.b.w. of 9-phenyl-acridine in

12 p.b.v. of ethylene glycol monoethyl ether

was spin-coated on a 25 μm thick polyethylene terephthalate film in sucha way that after drying (for 8 minutes using a fan dryer, then for 3minutes at 100° C. in a drying oven) a layer thickness of 25 μm wasobtained. The layer had a very uniform thickness and did not show anyvariations in coloration. The dry resist film was laminated to acopper-clad plate of an insulating resin as described in Example 16 andwas then exposed. After developing for 2 minutes, a cleanly developedimage of the original was obtained. Developer resistance and etchingresistance were excellent.

What is claimed is:
 1. A light-sensitive copying material, comprising:asupport sheet; and a dry light-sensitive layer which undergoes a changein solubility in an aqueous developer solution upon exposure to actiniclight so that, when said layer is selectively exposed to a light image,selected areas of said layer can be dissolved in an aqueous developersolution and the remaining areas will resist dissolution in said aqueousdeveloper solution to form a developed image corresponding to said lightimage, said light-sensitive layer comprising in admixture at least onelight-sensitive component and from about 0.01 to about 10 percent byweight of a surface-active polysiloxane copolymer consisting essentiallyof dialkylsiloxane units and oxyalkylene units corresponding to theformulae ##STR2## in which m and n are integers ranging from 1 to 4, ris an integer ranging from 2 to 5, x is an integer ranging from about 10to 100 and y is an integer ranging from about 25 to 350, wherein saidaqueous developer solution is comprised predominantly by weight ofwater.
 2. A light-sensitive copying material as claimed in claim 1,wherein said surface-active polysiloxane copolymer is contained in saidlight-sensitive layer in a quantity sufficient to reduce in a linearmanner by about 40 to 75 percent the spreading capacity on a support ofa coating solution containing the layer components.
 3. A light-sensitivecopying material as claimed in claim 1, wherein said surface-activepolysiloxane copolymer is contained in said light-sensitive layer in aquantity sufficient to reduce the surface tension of the light-sensitivelayer towards water by 2 to 12 mN/m, as compared with a layer which isfree of said polysiloxane.
 4. A light-sensitive copying material asclaimed in claim 1, wherein the solubility of said light-sensitive layerin an aqueous developer solution is increased by exposure to actiniclight.
 5. A light-sensitive copying material as claimed in claim 4,wherein said light-sensitive layer contains as the light-sensitivecomponent an o-quinone diazide.
 6. A light-sensitive copying material asclaimed in claim 1, wherein the solubility of said light-sensitive layerin an aqueous developer solution is reduced by exposure to actiniclight.
 7. A light-sensitive copying material as claimed in claim 6,wherein said light-sensitive layer contains as the light-sensitivecomponent a diazonium salt polycondensation product.
 8. Alight-sensitive copying material as claimed in claim 7, wherein saidlight-sensitive layer comprises a photopolymerizable layer.
 9. Alight-sensitive copying material produced by a process comprising thesteps of(1) coating a support sheet with a solution comprising inadmixture of at least one light-sensitive component and from about 0.005to about 1 percent of a surfactant dissolved in a single organic solventto form a thin layer of the solution on the support sheet, saidsurfactant comprising a surface-active polysiloxane copolymer consistingessentially of dialkylsiloxane units and oxyalkylene units correspondingto the formulae ##STR3## in which m and n are integers ranging from 1 to4, r is an integer ranging from 2 to 5, x is an integer ranging fromabout 10 to 100 and y is an integer ranging from about 25 to 350; and(2) drying the thin layer to remove the solvent therefrom to produce acloud-free, optically homogeneous light-sensitive layer of uniformcoloration and layer thickness on the support sheet, wherein saidlight-sensitive layer undergoes a change in solubility in an aqueousdeveloper solution upon exposure to actinic light so that, when saidlayer is selectively exposed to a light image, selected areas of saidlayer can be dissolved in an aqueous developer solution and theremaining areas will resist dissolution in said aqueous developersolution to form a developed image corresponding to said light image,and wherein said aqueous developer solution is comprised predominantlyby weight of water.
 10. A light-sensitive copying material as claimed inclaim 9, wherein said surface-active polysiloxane is present in aquantity sufficient to reduce the spreading capacity on the supportsheet of the coating solution in a linear manner by about 40 to 75percent.